A milestone diamond can be read as an instant even when the underlying activity occupies time. Before shortening an approval process to make a chart look cleaner, decide whether the item represents the review interval or the moment its result is received.

Use Project desktop for Windows and a clearly labelled practice plan. Write two different descriptions: Review package for approval and Approval received. The first describes an activity; the second describes an event. Neither label establishes that approval has actually happened.

Inspect the stored duration

Microsoft documents two milestone methods. In a Gantt Chart task row, entering 0 in Duration creates a zero-duration milestone. For a milestone that retains duration, select the task, open Task Information, choose Advanced, enter its duration and enable Mark task as milestone. Its diamond appears on the task's final day even though the task has duration.

Create a two-day Review package task and mark it as a milestone using the second method. Keep Start, Finish and Duration visible alongside the chart. Separately create the zero-day Approval received marker. Compare the fields, not just the two diamonds.

The useful question is whether a reader can reconstruct the intended interval. If the review begins on one day and finishes on another, a symbol shown only at its end can conceal that occupied span in a quick visual scan. Give the item a name that makes its meaning explicit.

Check the handover interpretation

Ask a colleague looking at the practice chart to identify which item allows time for review and which only marks receipt. Then show the duration fields. If their answer changes, the chart needs a clearer label or supporting explanation before it is used to discuss dates.

For an operational plan, retain the agreed review allowance and its rationale. Do not convert an interval to zero merely to obtain a diamond. Equally, avoid assigning an arbitrary duration to an event that only records a point in the schedule.

Finally, distinguish planned timing from completion evidence. A neatly positioned Approval received marker is still a planning representation until the responsible person confirms the event. The accepted result is a schedule whose stored duration and visible description express the same intended meaning.

Sources: Microsoft: milestones with duration.